Hubble telescope saw a star explode that stretched what's 'possible'

Stars have a very violent ending to their lives, they erupt in an explosion that is called a supernova, which is them basically collapsing on themselves.

Astronomers have a good idea of how and why stars go supernova at the end of their lifespans, especially for yellow stars. Most yellow stars have a protective layer of hydrogen that encases the extremely hot center which when looked upon would appear blue to our eyes. When a yellow star begins to go supernova all of the hydrogen layer that is encasing its insides is expelled outwards in a violent burst, but not if you are 2019yvr.

2019vyr didn't show any hydrogen around it in the years before it went supernova, which has puzzled scientists as this doesn't fit current scientific models. Charles Kilpatrick, lead author of the study said, "We haven't seen this scenario before. If a star explodes without hydrogen, it should be extremely blue - really, really hot. It's almost impossible for a star to be this cool without having hydrogen in its outer layer. We looked at every single stellar model that could explain a star like this, and every single model requires that the star had hydrogen, which, from its supernova, we know it did not. It stretches what's physically possible."

After the researchers observed the star exploding they proceeded to go back into the library of the Hubble Space Telescope to see what the star looked like in the years prior to the explosion. The star appeared to have interacted with the hydrogen of a neighboring star that had exploded, which caused the researchers to come up with a new theory that may explain what they observed when 2019yvr went supernova.

Kilpatrick explains, "Astronomers have suspected that stars undergo violent eruptions or death throes in the years before we see supernovae. This star's discovery provides some of the most direct evidence ever found that stars experience catastrophic eruptions, which cause them to lose mass before an explosion. If the star was having these eruptions, then it likely expelled its hydrogen several decades before it exploded."

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